An acoustic wave device is used for a filter, a duplexer or the like in a mobile communication terminal. The acoustic wave device is a Surface acoustic wave (SAW) resonator using a surface acoustic wave, a boundary acoustic wave resonator using a boundary acoustic wave, a film bulk acoustic wave resonator (FBAR) using a piezoelectric thin membrane or the like. Japanese Patent Application Publication No. 2008-227748 and Japanese Patent Application Publication No. 9-326447 disclose a technology sealing a piezoelectric substrate, on which an acoustic wave device is provided, with a sealing member made of a resin or the like as a method for protecting an acoustic wave device. And the documents disclose a wafer level package structure having a hollow structure for securing a functional region (a region for exciting an acoustic wave) in an acoustic wave device.
Japanese Patent Application Publication No. 2008-227748 discloses that piezoelectric substrates (chips) having an acoustic wave device having different filter characteristics are sealed with an identical sealing resin and are integrated, in a duplexer, a dual filter or the like structured with a plurality of acoustic wave filters. There is a method for dicing a wafer into chips, arraying the chips and integrating the chips by an interposer or the like, as a method for integrating different chips.
When a wafer is divided into chips by dicing and the chips are arrayed as a method of manufacturing an acoustic wave device including a plurality of acoustic wave filters, there is a problem that a manufacturing cost is increased if a device is miniaturized. And, there is little merit on forming a wafer level package having a hollow space, because an interposer forms a hollow space on a piezoelectric substrate.